There seems to be a lot of confusion among the better tuners on the forum as to what factors affect the R1 motor (or any motor for that matter) when it comes to getting more performance.

1) Cam timing - in simple terms this means when the intake and exhaust valves open via the cam lobes to provide the engine with the most gains. The most important aspect of cam timing is the intake valve closing event which determines how much cylinder pressure your engine will build. In other words if you close the intake valve early the cylinder will build more pressure as the piston compresses the mixture past BDC toward TDC and you'll have a bigger "bang" at lower revs. If you close it later you'll have less pressure but the engine will maintain it higher up in the rev range as the engine does not have to overcome "pumping losses" compressing the mixture. The exhaust cam works similarly but is not as important, only changing the rpm at which the engine will "overscavenge" due to valve overlap. An engine with greater valve overlap will run more poorly at low rpm than one with less overlap. All things being equal the first example may run better at higher rpm but the second example will develop better midrange (better street engine).

2) Lobe centers - basically the point of the crankshaft rotation where the cams are at their highest lift. In the case of the R1 the best #'s are 107 in and 104 ex. If you were to decrease the lobe center # for the intake, say 105 that means that at 105 deg. past TDC (meaning the crankshaft degrees) the intake valve will be at maximum lift. This also means that the intake cam will be "advanced" by 2 deg. and the intake valve will close earlier, meaning more cylinder pressure and better midrange with a slight loss of top end. Higher lobe center #'s for the intake mean the valve will close later and some midrange will be lost with a gain in "overrev" due to the piston having to compress less mixture in the cylinder as it rises toward TDC.

3) Clearances - the tightest most '98 - '03 street motors should be run is .030" piston to head, .040 piston to intake cam lobe and .075-.080 exhaust. That would be for an engine with higher lift cams, springs and a higher redline than the stock 11,600. The exhaust #'s are higher as the exhaust valve will stretch at higher rpm due to the heat involved. These tolerances could be tightened up for a race engine that is rebuilt every race but for a long term street engine these are pretty good. When Attack racing was campaigning the early R1's they would tighten up the valve/piston clearances to the point that you would see the imprint of the valves in the carbon of the piston pocket and ran them this way. Obviously not the best thing for a street motor.
The thing that affects these clearances at high rpm is rod stretch, valve stretch, valve spring float, crankshaft deflection and cam chain wear.

An interesting read yamaguy, thanks for posting it up. I've been debating cam timing on my headwork thread and long and short appears to be there's no substitute for experimenting to a degree once you have approximate starting positions.

You say that the best numbers for an R1 are 107in and 104ex. Is this a number you came up with after extensive testing on your motor or something you've been told? Also, what year R1 as the numbers will vary with model? It'll also be dependant on other mods to the engine. I see from your signature you run an 02 with quite a lot of work done.

I've learnt from the research I've done not to take other people's numbers as gospel as testing has shown even on the same models of standard bikes, numbers can vary a few degrees to get the optimum.

Sorry if this sounds like I'm sceptical but this does seem to be a very grey area. I'm sure this'll be a very interesting thread though

There seems to be a lot of confusion among the better tuners on the forum as to what factors affect the R1 motor (or any motor for that matter) when it comes to getting more performance.

1) Cam timing - in simple terms this means when the intake and exhaust valves open via the cam lobes to provide the engine with the most gains. The most important aspect of cam timing is the intake valve closing event which determines how much cylinder pressure your engine will build. In other words if you close the intake valve early the cylinder will build more pressure as the piston compresses the mixture past BDC toward TDC and you'll have a bigger "bang" at lower revs. If you close it later you'll have less pressure but the engine will maintain it higher up in the rev range as the engine does not have to overcome "pumping losses" compressing the mixture. The exhaust cam works similarly but is not as important, only changing the rpm at which the engine will "overscavenge" due to valve overlap. An engine with greater valve overlap will run more poorly at low rpm than one with less overlap. All things being equal the first example may run better at higher rpm but the second example will develop better midrange (better street engine).

2) Lobe centers - basically the point of the crankshaft rotation where the cams are at their highest lift. In the case of the R1 the best #'s are 107 in and 104 ex. If you were to decrease the lobe center # for the intake, say 105 that means that at 105 deg. past TDC (meaning the crankshaft degrees) the intake valve will be at maximum lift. This also means that the intake cam will be "advanced" by 2 deg. and the intake valve will close earlier, meaning more cylinder pressure and better midrange with a slight loss of top end. Higher lobe center #'s for the intake mean the valve will close later and some midrange will be lost with a gain in "overrev" due to the piston having to compress less mixture in the cylinder as it rises toward TDC.

3) Clearances - the tightest most street motors should be run is .030" piston to head, '040 piston to intake cam lobe and .075-.080 exhaust. The exhaust #'s are higher as the exhaust valve will stretch at higher rpm due to the heat involved. These tolerances could be tightened up for a race engine that is rebuilt every race but for a long term street engine these are pretty good. When Attack racing was campaigning the early R1's they would tighten up the valve/piston clearances to the point that you would see the imprint of the valves in the carbon of the piston pocket and ran them this way. Obviously not the best thing for a street motor.
The thing that affects these clearances at high rpm is rod stretch, valve stretch, valve spring float, crankshaft deflection and cam chain wear.

HI there,

I see you are running YEC cams and 03 pistons, am I right? First I thought that 03 pistons are the same with the 2001 5JJ R1... I am not aware of anything different between 01 and 03 pistons. Anyway the YEC cams require a certain (rather high) compression to work proprerly. How much you have skimmed your head and do you know what compression you actually have right now? As for the piston to valve clearence 40 thou for inlet and 80 thou for ex is way too much even for street motor. If a valve will hit a piston that will only happen at very high rpm as you know, and for a street motor its not likely you will be keeping it in the reds for such a prolonged time. A rather reduced 35 thou for the intake (0.875mm) and a 50 thou for the exhaust (1.25mm) is also very reliable piston to valve clearence on both street/race motors.
As for the squise (piston to head) 25-28 thou is fine (0.7mm) and its what yamaha officially recomends on all their motors. STD R1 squice on a 5PW is 0.8mm. Note however that the rods of the R1 are pretty good and you can run even tighter 0.6mm squise with no problems.

As for your post above, 105/105 lobe centres doesnt do the trick for me for the midrange (at least with YEC cams that they seem to be high rpm oriented) so I was wondering if you guys have more suggestions. Especially with ramair boxes and would appreciate if you could say what size jets are you using too.

You say that the best numbers for an R1 are 107in and 104ex. Is this a number you came up with after extensive testing on your motor or something you've been told? Also, what year R1 as the numbers will vary with model? It'll also be dependant on other mods to the engine. I see from your signature you run an 02 with quite a lot of work done.

Those cam #'s are with the clearances as described in the first thread. They were obtained from Graves and Yamaha Canada as being as compromise between longevity and engine performance. You can always change them but the clearances should be maintained.

I see you are running YEC cams and 03 pistons, am I right? First I thought that 03 pistons are the same with the 2001 5JJ R1... I am not aware of anything different between 01 and 03 pistons. Anyway the YEC cams require a certain (rather high) compression to work proprerly. How much you have skimmed your head and do you know what compression you actually have right now? As for the piston to valve clearence 40 thou for inlet and 80 thou for ex is way too much even for street motor. If a valve will hit a piston that will only happen at very high rpm as you know, and for a street motor its not likely you will be keeping it in the reds for such a prolonged time. A rather reduced 35 thou for the intake (0.875mm) and a 50 thou for the exhaust (1.25mm) is also very reliable piston to valve clearence on both street/race motors.
As for the squise (piston to head) 25-28 thou is fine (0.7mm) and its what yamaha officially recomends on all their motors. STD R1 squice on a 5PW is 0.8mm. Note however that the rods of the R1 are pretty good and you can run even tighter 0.6mm squise with no problems.

As for your post above, 105/105 lobe centres doesnt do the trick for me for the midrange (at least with YEC cams that they seem to be high rpm oriented) so I was wondering if you guys have more suggestions. Especially with ramair boxes and would appreciate if you could say what size jets are you using too.

Regards,

'02 and '03 pistons have a slightly larger od (.0015") so they fit in the bore a little tighter for better sealing.

Head is angle skimmed .015"in .020 ex, very common. Compression ratio is around 13:1, but I would have to measure it to be sure.

The only # that you recommend that is far off from mine is the piston to valve on the exhaust side, if you want to run them that tight that's up to you. My numbers were'nt pulled out of the air, they were given to me by 2 very reputable engine shops that build race motors. They are a compromise between performance and longevity.

The 105 l.c. was just an example of what you would do if you wanted to advance the intake cam from 107 deg., that's all.

The only # that you recommend that is far off from mine is the piston to valve on the exhaust side, if you want to run them that tight that's up to you. My numbers were'nt pulled out of the air, they were given to me by 2 very reputable engine shops that build race motors. They are a compromise between performance and longevity.

Hi,
Yes I believe it, however Virgin yamaha team in the UK are running these clearences, as well other ppl I know and they do racing. All OK no blown off motors even with modified ECUs that allow revving ~13.500 rpm! We even use STD valve springs, they are good up to 15000 rpm. The only thing that stops an early R1 motor of revving over 13.500 are its valves (good for up to 13.500rpm) and most importantly its rods definitely not good for more than a 13500 especially if you are an aggressive rider. Polishing the rods and shot pining them helps but still... As I said I am talking here for the 98-03 R1 motor not the latest ones!

To re-capture what you said: You are using YEC cams with an angle milled head 15 thou in/20 thou ex and a STD head gasket. Am I right here? What is your timing?

Hi,
Yes I believe it, however Virgin yamaha team in the UK are running these clearences, as well other ppl I know and they do racing. All OK no blown off motors even with modified ECUs that allow revving ~13.500 rpm! We even use STD valve springs, they are good up to 15000 rpm. The only thing that stops an early R1 motor of revving over 13.500 are its valves (good for up to 13.500rpm) and most importantly its rods definitely not good for more than a 13500 especially if you are an aggressive rider. Polishing the rods and shot pining them helps but still... As I said I am talking here for the 98-03 R1 motor not the latest ones!

To re-capture what you said: You are using YEC cams with an angle milled head 15 thou in/20 thou ex and a STD head gasket. Am I right here? What is your timing?

so true, i know martinc did some testing and has some info on it. still no magic #'s that likes all mods and performs well. curious to see where mine will be with modified head and what it does to cam timing.

still confused how anyone can say for sure 107/104 are the magic numbers for cam timing in an R1 when you don't know what mods have been done, what cams are being used, what performance is desired...

And still curious as to what timing you have actually tested you're self.

Threads like this add alot of cunfusion to people searching for information I think.

Hi
I have been reading this thread and that headwork winter project thread. I'm taking apart my first engine and i'm really eager to learn. I'm doing 00 engine with stock cams,springs,valves,gasket. I have spare head which i'm going to check properly, lapping valves and seats and setting cam timing. I haven't found specs for that and i'm referring to 02 specs because it looks like they are the same( head,cams etc.).
First of all STD cam lobe centers are INT 105, EX 102. I would like to gain some midrange power more without loosing too much from top. What would be best solution? Just setting it to STD?
Next question may sound stupid but, how you measure p-v clearance?
How much is it possible to play with cam timing with that clearance?

NPN I don't know what magic Numbers will work for you, but I can answer a few of your questions.

There are three ways I know of to check piston to valve clearance.

You can use clay on top of the piston. With this method you pull the head off, coat the combustion chamber and piston top with a light coat of oil (so the clay won't stick) and then re assemble the head and cams, then spin the motor over two full revolutions, then remove the head again and measure the impression made in the clay by the valves.

I personally don't love this method, though it is widely used. I find it more difficult to get accurate numbers from the very flexibly clay. Also i like to degree the cams before i check to v and this may well give you a false impression in the clay as you will have to rotate the motor over several times just to get the cams degreed.

Another method is to use a screwdriver and depress the shim bucket. With this method you set up a dial indicator that reads the actual valve bucket movement. once you do that you will rotate the piston just past TDC on the intake stroke and you will use a screwdriver or similar wedge to depress the valve bucket until you get an idea where the tight spot is. Once you find the tight spot, or spot with the tightest p to v clearance you zero you're dial indicator and take a reading while depressing the valve far enough o contact the piston. You then will take readings in 1 degree crank rotation increments until you find the tightest spot. You will be re zeroing the dial indicator for each reading.

The tight spot on the intake will be just past TDC on the intake stroke (maybe between 10 and 20 degrees past TDC) and the tight spot on the exhaust will be just before TDC on the exhaust stroke as the piston is chasing the valve closed.

this is also not my ideal method as it worries me to no end that I may scratch the cam lobe or the valve bucket with the prying instrument. Also the valve springs are very hard to depress making you exert allot of force while trying to take a precise reading.

The last way I know to do it, and the one I prefer is to use "checker springs". They are just light springs that you can easily compress with two fingers that are installed in the place of the normal valve springs. You just need 4 or 5 of them and they can be had pretty cheap at any hardware store.

With this method you remove the head, install the weaker springs in place of the regular valve springs, reinstall the head, degree the cams, set up a dial indicator to read directly off the valve bucket, and just as before rotate the piston just past TDC on the intake stroke and start finding the tight spot and measure it.

this method I like allot, it's super easy and less chance for me to scratch anything.

I just install the valves for one cylinder, degree the cams, and then take my readings. It's super easy to find the tight spot as you can hold the valve bucket down with your finger and follow the piston to feel the tightest clearance. Then just zero your indicator and start taking readings till you find the tightest spot.

Any of the methods will work, and have all been used a zillion times by people way smarter than me.

Important things to remember are : You need to be using the head gasket that will be used on assembly with the head torqued to proper specs, the cams MUST be DEGREED first!! Everything has to be exactly as it will be on final assembly.

I have not done any R1 motors myself, but it is my understanding that they do not have allot of room (P to V clearance) for a broad range of cam timing adjustments. Small cam timing changes can have a huge effect on P to V, so you must check it any time cam timing is changed.

Yamaha valve springs are pretty cheap (price wise not quality wise) so it would be a great investment for anyone building one of the R1 or R6 motors to buy new OEM springs at the least on a rebuild.

As far as the valve timing measuring points it's pretty simple. To measure the timing they use a set lift to take timing measurements. That means that they start measuring when the valve lifts a set amount, and stop measuring when the valve reaches that same amount right before it closes. When you degree a cam you will be doing the same thing. You will set up your dial indicator and degree wheel, and you will rotate the motor while watching the dial indicator, once it moves a set amount you take a reading off the wheel then record it, then continue rotating the motor until you reach that same measurement right before the valve closes. I use .050 when i do cams, but it actually makes no difference what lift you use.

Cam manufacturers are in business to sell cams, and the buying public like big numbers, so some companies start measuring a a smaller lift to make the overall numbers look bigger. If you use .040 as your set lift then your duration (how long the valve is held open) will look bigger on paper than if you used .050 to measure at.

I know some of this probably makes no sense to you at the moment, but I promise once you do it you will understand. it's not really all that hard to do, just takes allot of time and patience.

My only other suggestion would be to use a good quality assembly lube, as you will be rotating the motor over plenty before it gets oil in it.

Thank's JAYSTENSEC4CYL. That was really good information. Probably i start with STD lobe centers and trying to get that clearance measured. I'm going to print all these posts and getting started with my spare head in near future. It's really awesome how helpful guys in this forum really are. Thank's to all of you! I really haven't decided what to do with springs, valves, sprokets etc. It depends in what condition they are. This head have something like 40000km by now, and my engine have the same. I have to admit that i'm really proud if i don't blow my engine after all this.

NPN I'm sure you'll be fine. Good on you for wanting to have a go. It's great fun and very staisfying doing that kind of work for the first time, especially on your own bike. Just take your time and be methodical. Take photos and notes if it helps, just for peace of mind more than anything else.

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